The 11th annual World
Computer-Bridge Championship, sponsored by the American Contract Bridge League
(ACBL) and the World Bridge Federation (WBF), was held in Shanghai, China
alongside the WBF’s 38th World Team Championships.

History

The ACBL inaugurated an annual
computer-bridge championship in 1997 as a way of encouraging computer-bridge
software developers to accelerate their robots’ development to expert class,
with the hopeful result of more software development for educational purposes
and generally to promote bridge.The
WBF also supports this event and starting in 1999 it became an ACBL/WBF joint
venture.Since its inception in 1997,
the championship has been held every year alongside an important bridge
championship.The eleven championships
have been held four times at ACBL North American Bridge Championships, six
times at WBF World Championships and once at the European Bridge League’s first
European Open Championship.For a
complete history and details of previous championships go to www.computerbridge.com or www.ny-bridge.com/allevy/computerbridge

Technical remarks

A bridge “table” consists of a central server (CS) that
manages the game, and four connecting computers that “seat” the robots.The CS distributes the four hands of each
board to the robots.Play proceeds
automatically, with pauses for exchanges of information when explanations of
bids are necessary.The CS receives and
passes information from and to the robots and records the bidding and
play.This year P4 3 GHz/512 MB PCs
were used, running under Windows XP.Unfortunately the computers where shy of the advertised specifications,
which was not an issue for most of the contestants.The timing of play was set at two minutes per pair per deal.

The contestants submit their Convention Card (CC),
containing their bidding and carding methods, one month before the competition
so that the others can prepare.This
information is stored in the opponent robots’ memories before play begins.Nevertheless, there are some alerts
(explanations) that occur during the bidding and are manually input into memory
during play.

Without getting into
the details, most of the robots are programmed with a combination of
knowledge-based AI (sets of rules) and search-based AI (simulations).

Play format

The format is team play.Two teams play each other, with each team using four identical robots,
one pair sitting North-South at one table and one pair sitting East-West at the
other table.

This six-day event starts with a
32-board round-robin, each team playing the other seven.The top four robot teams advance to the
semifinal knockout stage, a 64-board semifinal followed by a 64-board
final.The round-robin is scored on an
International 30-VP scale.

X

WBridge5’s results are impressive,
winning six of its eight round-robin matches, tying the other two against
finalist Bridge Baron and Shark Bridge, and convincingly winning its semi-final
and final matches.

The Play

Some of the boards played in the sixth and seventh round-robin matches
were played earlier in the “human” championships which are the Bermuda Bowl
(Open Team Championship), Venice Cup (Women’s Team Championship), and Senior
Bowl (Senior Team Championship).Two
boards from the seventh round follow.In the round robin of the computer championship each hand was played 8
times, while in the human championships each board was played 22 times.

Board 1. Dealer
North. None Vulnerable.

♠ K 6 5 4 3♥ J 9♦
K 4 2
♣ A J 10

♠ 10 7♥ A Q 8 6 3 2♦
3
♣ 7 4 3 2

North

WestEast

South

♠ 9 2♥ 10 4♦
A J 8 7 6
♣ K 9 6 5

♠ A Q J 8♥ K 7 5♦
Q 10 9 5
♣ Q 8

Board 1 is a routine board.It's
used to show that, on flat boards, the robots reach normal contracts and make
the normal number of tricks.In the
human championships, 4♠ was reached
63 out of 66 times and 3NT was reached the other three times.4♠
was made five times, four times with a club lead away from the King, and once
on poor defense after the ♥10
lead.3NT was defeated each time.The robots reached 4♠ all eight times, with all defeated one or two
tricks.No defender led away from the
♣K.

Board 2. Dealer
East. N-S Vulnerable.

♠ K Q J 8 7 6
3♥ 10 7♦
6
♣ K 10 2

♠ -♥ J 8 6 5 2♦
A K J 8 2
♣ Q 4 3

North

WestEast

South

♠ 9 4♥ K Q 9 3♦
4
♣ J 9 8 7 6 5

♠ A 10 5 2♥ A 4♦
Q 10 9 7 5 3
♣ A

Board 2 is much more interesting.The robots reached the cold 6♠,
or sacrificed in 7♥50% of the time, compared to less than 25% of the
time for the humans.

Bermuda Bowl

Venice Cup

Senior Bowl

Robots

6♠(x)

5/22

3/22

5/22

3/8

7♥x

1/22

0/22

1/22

1/8

West

North

East

South

Versace

Chagas

Laurie

Villas Boas

Pass

1♦

1♥

4♠

5♥

6♠

All Pass

West

North

East

South

Versace

Chagas

Laurie

Boas

Pass

1♦

1♥

2♥ (transfer)

4♥

4♠

All Pass

When West overcalled 1♥, either North and/or East-West preempted
the auction and North-South had to be less than scientific, as is often the
case with preempts.In the Bermuda Bowl
Italy-Brazil match, pitting two of the best teams in the world, Boas for Brazil
gambled that there would not be two diamond losers, while Bocchi-Duboin for
Italy didn't venture past 4♠.

West

North

East

South

RoboBridge

WBridge5

RoboBridge

WBridge5

Pass

1♦

Pass

1♠

Pass

3♠

Pass

4♣

Pass

4♥

Pass

4NT

Pass

5♣ (0-3)

Pass

6♠

All Pass

WBridge5 had an excellent auction when RoboBridge passed over 1♦.

West

North

East

South

Jack

Micro Bridge

Jack

Micro Bridge

Micro Bridge

Jack

Micro Bridge

Jack

Pass

1♦

1♥

1♠

3♥

4♠

Pass

4NT

Pass

5♣/5♦ (0-3)

Pass/Dbl

6♠

Pass

Pass

Pass/Dbl

In the Jack-Micro Bridge match, both North robots judged that it was a good
bet that South had first or second round control of hearts.When Jack responded 5♦ to KCB, West doubled for
the lead, and then doubled the final contract.Jack gained 6 IMPs.

Final
match

The final match pitted WBridge5 against Bridge
Baron.Throughout the tournament
WBridge5’s aggressive bidding resulted in bidding, and making, more slams then
its opponents.In the final match this
aggressive bidding paid off.The final
match, between WBridge5 and Bridge Baron, contained twelve boards where one or
both sides were in slam.The result was
a net gain for WBridge5 of 109 IMPs, more than the margin of victory.

Two boards from the final match follow.

Board 8, 2nd
segment. Dealer West. None Vulnerable.

♠ 3 ♥ A K 10 ♦
A 4
♣ K J 10 8 7 5 4

♠ J 8 6 ♥ Q 8 5 4 3 2 ♦
K Q 8 2
♣ -

North

WestEast

South

♠ Q 10 5 2 ♥ 9 7 ♦
J 9 7 5 3
♣ 9 2

♠ A K 9 7 4 ♥ J 6 ♦
10 6
♣ A Q 6 3

West

North

East

South

Bridge Baron

WBridge5

Bridge Baron

WBridge5

Pass

1♣

Pass

1♠

Dbl

3♣

3♦

4NT

Pass

5♣(0 or 3 KCs)

Pass

5NT

Pass

6♦(1 King)

Pass

7♣

All Pass

This gained 14 IMPs for
WBridge5.At the other table WBridge5
West opened 2♥, North Doubled, and
Bridge Baron South jumped to 4♠ and
played it there for +420.

Board 5, 4th
segment. Dealer North. N-S Vulnerable.

♠ K Q 6 3 ♥ 4 ♦
A 8 7 6 3
♣ Q 6 4

♠ 5 4 2 ♥ J 10 8 5 ♦
10 9
♣ 7 5 3 2

North

WestEast

South

♠ 10 ♥ A Q 9 2 ♦
K J 4 2
♣ K 10 9 8

♠ A J 9 8 7 ♥ K 7 6 3 ♦
Q 5
♣ A J

West

North

East

South

Bridge Baron

WBridge5

Bridge Baron

WBridge5

1♦

Pass

1♠

Pass

2♠

Pass

4♣

Pass

4♦

Pass

4♥

Pass

4♠

Pass

4NT

Pass

5♠ (2 + ♠Q)

Pass

6♠

All Pass

The slam seems impossible and can be defeated on a diamond lead.Bridge Baron made the normal lead of the ♥J to East's ♥A.East returned the trump 10, declarer winning
the Jack.The play proceeded ♥K, heart ruff, club finesse, heart ruff,
running trumps coming down to a three-card ending.

♠ -♥ -

♦
A
♣ Q 6

♠ -♥ -♦
10 9
♣ 7

North

WestEast

South

♠ -♥ -♦
K (J)
♣ K (10)

♠ -♥ -♦
Q 5
♣ A

East, shown here with four cards, must discard and cannot
guard both the ♦K
and the ♣K.At the table East
blanked the ♦K,
hoping partner had the ♦Q.WBridge5 guessed correctly, playing the ♦A, ♣A, ♦Q.If East unguards the ♣K, declarer
plays ♣A, ♦A,
♣Q.WBridge5 won 11 IMPs when
Bridge Baron played in 4♠, making
5, at the other table.

General
remarks

Overall, the play continues to improve.The play often appears “expert” as
demonstrated by some of these hands, and sometimes appears weak.This is similar to “less-than” top-level
bridge, but a little more frequent.

Shark Bridge, a second-year entry, improved
tremendously.Bridge Baron’s semifinal
win over Jack is impressive.Jack’s
results are less than expected, due partially to some bad luck.Q-Plus Bridge and Micro Bridge are
consistent, but appear to fall short of the top competitors, namely WBridge5,
Jack and Bridge Baron.For newcomers
RoboBridge and TUT Bridge, this was a learning experience.Hopefully, they will be back stronger next
year.

WBridge5 is impressive.Its known aggressive style gained much more then it lost.Besides the clear gains in the finals, where
it had no significant losses due to its aggressive bidding, it also gained,
much less dramatically, in its earlier matches.It is clear that WBridge5 is geared for slam bidding, evaluating
and reevaluating hands very well, reaching many slams that are based on fit and
distribution, not on HCPs alone.